RPO code question

[big83chevy4x4]

my buddy bought a mid-late 70s C&C c30 (pre 78 as vin is on door jam), we were looking on the RPO code list and there was a "J44 - locking rear diff" i can't find J44 in any rpo code list. this rear has i think a detroit locker in it, but im thinking its a factory install now that i looked at the codes, but i thought they only came in the military trucks?

 

[divorced]

I can't find anything on it. It it a 14 bolt? I always though that the "J" codes were for brake options.

 

[1985K20]

http://polariswebdesign.com/truckfiles/GMRPOCodes.pdf

 

[atho]

it should be a G-- if its a diff. on the '66 C/20 that I got my eaton axle w/ detroit locker from, it had "G86 No-Spin" listed on the GB sticker. on that polaris site it just says G86 is a limited slip, must have changed over the years.

i asked a while back, and it was pretty much determined by everyone here that the detroit was not an option anymore after '72, except for the CUCV's. even then, no one could come up with the specific RPO for the CUCV locker.

i'd just bust off the diff cover to see whats up.

 

[R72K5]

lol G80 is the locking diff RPO, same as for pos trac and so forth

could be either posi or gov lok, either one, pull the cover and find out!

J codes are for brake RPO's yes

good luck

 

[divorced]

lol G80 is the locking diff RPO, same as for pos trac and so forth

G86 is also a limited slip. "Axle, Rear, Limited-Slip"

http://www.c2e.info/rpocodes/MODERNGMRPO.html

 

[big83chevy4x4]

i pulled the diff a while ago, it is not a gov loc. its an aftermarket locker, most likely a detroit locker, inside an open carrier. all the pics i have seen of the detroit inside the carrier looks exactly like it. like i said i never found it on any rpo code list, but it is there, J44 locking rear diff. ill get a pic next time im out there.

 

[divorced]

Is it a 4.56 ratio?

 

[big83chevy4x4]

yep